The Nullarbor Plain, located in southern Australia along the Great Australian Bight, covers about 200,000 km², making it one of the world’s largest exposed karst surfaces. Despite the dominant arid and semi-arid climate limiting karst processes, the Nullarbor has become karstified over 14 million years since marine transgression and tectonic uplift. Among its most common yet understudied surface features are shallow karst depressions known as dayas. This master’s thesis focuses on the geomorphological analysis of dayas on the Nullarbor Plain. The research combines a review of literature on arid karst, dayas, and the region itself, with morphographic analysis using semi-automatic detection, morphometric and sedimentological analyses, and an assessment of recent hydrological activity. The results show that daya development depends on preserved paleotopography, precipitation, and lithologic characteristics, with their maximum age likely dating back to the Pliocene. Aeolian and fluvial geomorphic processes concentrate poorly permeable in the dayas, which allows water from flash-floods to remain for longer periods and likely causes lateral corrosion and widening of the depressions. According to our findings, some of this water infiltrates into the karst aquifer, indicating that dayas are one of the few surface karst features where karst processes are active.
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